This invention relates to a lubricant oil composition and more particularly, to a lubricant oil composition containing a friction modifier which is a reaction product of a maleic anhydride and an amine.
With the increase in energy costs, the cost of petroleum products derived from crude oil has escalated rapidly. These costs are particularly burdensome to users of transportation fuels such as railroads and ships which consume large quantities of petroleum products.
Railroad and ship diesel engines both consume thousands of gallons of now more expensive diesel fuel each year. These fuel charges are passed along to the consumer in the form of higher shipping costs.
For example, the largest marine diesel engines used for ship propulsion are slow speed marine diesel engines. These engines are quite large with the larger units approaching 2,000 tonnes in weight and upwards of 30 meters in length and 50 meters in height. These engines can revolve at rates ranging from about 100 to 125 revolutions per minute.
The slow speed marine diesel engines are unique in their design. The crankcase of the large slow speed single acting, two stroke crosshead type of engine is completely separate from the combustion chambers of the engine. Because of this, its lubrication requirement differs from that of a typical diesel engine. In particular, the upper cylinder portion of the slow speed diesel engine which is not in direct communication with the crankcase of the engine, has its own lubrication system with lubrication requirements that are quite different from that of the crankcase lubricant. Generally, and for reasons of economy, the fuel employed in the large slow speed diesel engines are residual fuels having relatively high levels of sulfur. This generally requires the employment of highly overbased lubricating oil composition in order to counteract the acidity generated during the combustion of the sulfur containing fuel. As a result, the typical cylinder lubricating oil composition for a slow speed diesel engine will have an alkalinity level expressed as Total Base Number ranging between about 50 and 100.
The fuel consumption rate of a marine diesel engine of the size contemplated herein ranges upwards of 4500 liters of fuel per hour. One method of reducing the overall fuel consumption of such an engine, as well as other diesel engines, is in reducing frictional losses within the engine by using a lubricant composition which materially reduces such frictional losses. Reductions in engine friction result in significant fuel savings.
Numerous means have been employed to reduce the friction in internal combustion engines. These range from the use of lower viscosity lubricating oils or mixtures of mineral and synthetic lubricating oils as well as to the incorporation of friction-reducing additives such as graphite, molybdenum compounds and other chemical additives. There are limits to the extent to which the viscosity of a lubricating oil can be reduced for the purpose of reducing friction. Generally, a lubricating oil having too light a viscosity will fail to prevent metal-to-metal contact during high load operating conditions with the result that unacceptable wear will occur in the engine.
A preferred method of modifying a lubricant composition, whether for the cylinder or for the crankcase, to reduce frictional losses involves the addition of an additive which reduces the friction within the engine without adversely affecting the engine or the lubricating properties of the lubricating oil while maintaining its antifriction properties over the extended service life and operating conditions of the engine.
Coassigned U.S. Pat. No. 4,207,079, incorporated herein by reference, sets forth a primary aliphatic hydrocarbon amino alkenyl-substituted asparagine which can be used in the lubricant composition of the present invention. Further, the Patent sets forth the use of the asparagine in fuel compositions to improve the detergency of such composition.
Coassigned U.S. Pat. No. 4,204,841 sets forth the same asparagine with other additives for use in fuel oil compositions wherein the added asparagine with other additive acts as a detergent. Coassigned U.S. Pat. No. 3,905,781 and No. 3,773,479 set forth alkyl-substituted asparagines which are also used as additives in motor fuel compositions.